Sensitization of photographic silver halide emulsions containing colorforming compounds by 1 1-bis-sulfonyl alkanes

ABSTRACT

THE SPEED OF PHOTOGRAPHIC SILVER HALIDE EMULSIONS CONTAINING COLOR-FORMING COUPLERS IS INCREASED BY PROCESSING IN THE PRESENCE OF 1,1-BIS-SULFONYL ALKANE SPEED INCREASING AGENTS.

United States Patent SENSITIZATION 0F PHOTOGRAPHIC SILVER HALIDE EMULSIONS CGNTAINING COLOR- FORMING COMPOUNDS BY 1,1-BIS-SUL- FONYL ALKANES Paul H. Stewart and Donald W. Heseltine, Rochester,

N.Y1.\,{ assignors to Eastman Kodak Company, Rochester, .Y.

No Drawing. Filed June 1, 1970, Ser. No. 42,605

Int. Cl. G03c 1/28, 1/40 US. Cl. 96-107 17 Claims ABSTRACT OF THE DISCLOSURE The speed of photographic silver halide emulsions containing color-forming couplers is increased by processing in the presence of 1,1-bis-sulfonyl alkane speed increasing agents.

This invention relates to the art of photography and to photographic silver halide emulsions employed therein. More particularly, this invention relates to sensitizing photographic silver halide emulsions containing colorforming compounds, or couplers.

Chromogenic systems in Which photographic silver halide emulsions are employed in combination with various color-forming compounds or couplers, that react with the oxidation products of color developers to provide subtractively-colored images are well known to the art of photography. The couplers may be contained either in the processing solution or in the photographic emulsion. The color-forming compounds employed include, for example, pyrazolone couplers for the formation of a magenta image, phenolic couplers for the formation of a cyan image, and open-chain couplers containing a reactive methylene group for the formation of a yellow image. If the couplers are incorporated in a photographic silver halide emulsion layer, they are characterized by nondiffusing properties with respect to the particular silver halide emulsions in which they are incorporated.

Various methods have been proposed for increasing the sensitivity of photographic silver halide emulsions, other than methods of optical or spectral sensitization, which involve the incorporation of certain colored com pounds or dyes in the emulsions. Thus, for example, US. Patent No. 3,046,129 to Graham et al. describes the incorporation of certain linear thioether polymers in photographic silver halide emulsions in combination with color couplers in order to increase speed by their presence during exposure and processing.

Likewise, it has been suggested to add polyalkylene glycols, cationic surface active agents and thioethers, or combinations of these, to silver halide emulsions as speed increasing compounds. Such speed-increasing compounds are described in U.S. Pat. 2,886,437 to Piper; US. Pat. 3,046,934 to Dann et al.; US. Pat. 2,944,900 to Carroll et al.; and US. Pat. 3,294,540 to Goffe. It would be highly desirable to provide a novel class of speed-increasing addenda for incorporated coupler emulsion systems.

It is, therefore, an object of the present invention to provide novel photosensitive elements and photographic silver halide emulsions containing color-forming compounds having increased speed.

Another object of the present invention is to provide a process for increasing the speed of photographic silver halide emulsions containing a color-forming compound.

It has now been found that the speed of a photographic silver halide emulsion with an incorporated color coupler can be materially increased by incorporating therein a 1,1 bis-sulfonyl alkane (or B-disulfone) speedincreasing agent.

3,625,699 Patented Dec. 7, 1971 The B-disulfones and their chemical reactions have been described in the literature. For example, the preparation of these compounds and reactions in which they are involved is described in Suter, Organic Chemistry of Sulfur, on pages 735 and 739. However, it has now been discovered that particular fl-disulfones, namely, 1,1-bis sulfonyl alkanes, provide increased speed in systems employing incorporated couplers.

Suitable 1,1 bis-sulfonyl alkanes used in the present invention can be represented by the general formula wherein R and R each represents a lower alkyl group and R represents H or a lower alkyl group. The term lower alkyl as employed herein is preferably an alkyl group containing from about 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl, isopropyl, butyl and the like. The term alkyl as employed herein also includes substituted alkyl groups, and is preferably a substituted lower alkyl group containing from 1 to 4 carbon atoms. Thus, substituted lower alkyl groups such as a hydroxyalkyl group, e.g., B-hydroxyethyl, w-hydroxybutyl, etc.; an alkoxyalkyl group, e.g., fi-methoxyethyl, w-butoxybutyl, etc.; a carboxyalkyl group, e.g., p-carboxyethyl, w-carboxybutyl, etc.; a sulfoalkyl group, e.g., fi-sulfoethyl, w-sulfobutyl, etc.; a sulfatoalkyl group, e.g., B-sulfatoethyl, w-sulfatobutyl, etc.; an acryloxyalkyl group, e.g., fl-acetoxyethyl, w-butyryloxybutyl, etc.; an alkoxycarbonylalkyl group, e.g. fl-methoxycarbonylethyl, w-ethoxycarbonylbutyl, etc. are preferred.

1,1 bis-sulfonyl alkanes within the above formula include 1,1 bis-(methylsulfonyl)ethane; 1,1 bis-(ethylsulfonyl)- ethane; 1,1 bis-(methylsulfonyl)propane; 1,1 bis- (ethylsulfonyl propane; l-ethylsulfonyll-methylsulfonyl methane; l-ethylsulfonyl-l-methylsulfonyl ethane; etc. Especially preferred 1,1 bis-sulfonyl alkanes are bis(methylsulfonyl)methane, bis(ethylsulfonyl)methane, bis(fi-hydroxyethylsulfonyl methane, bis (carboxymethylsulfonyl) methane, and bis(fi-carboxyethylsulfonyl)methane.

The disulfones of the present invention are efiectively employed in photographic silver halide emulsions in combination with various color-forming compounds or couplers, which react with the oxidation products of color developers, such as aromatic primary amino color developing agents e.g., p-phenylenediarnine developers, to provide subtractively-colored images. Likewise, the disulfones of the invention can be utilized in one or more layers of a photosensitive element contiguous to the silver halide emulsion.

The amount of disulfone to be employed may vary over a fairly wide range. The optimum amount of the particular disulfone employed will vary somewhat from emulsion to emulsion and from disulfone to disulfone. Generally, an effective sensitizing concentration is from about 0.1 to about 1.0 mole of the disulfone per mole of silver halide in the silver halide emulsion.

Any of the customary types of color-forming couplers can be employed in the present invention. Such couplers can be of the type which can be dispersed in a high-boiling crystalloidal compound, which may be used as a vehicle for incorporating the color-forming compound in the photographic emulsion. Alternatively, the couplers may be of the fat-tail varieties (for example, see F.I.A.T., Final Report, No. 721) which may be dispersed in the photographic silver halide emulsions. Both of these types of couplers are characterized by non-diffusing properties in the particular silver halide emulsions in which they are incorporated. The couplers, or color-forming compounds, can be incorporated in the silver halide emulsion by any of the common methods known to those skilled in the art. Likewise, the disulfones of the present invention may be added to photographic emulsions using any of the techniques well known in emulsion making. For example, the disulfones can be dissolved in a suitable solvent and added to the silver halide emulsion or they may be added to the emulsion in the form of a finely divided dispersion, such as is described in Fierke et al., U.S. Patent 2,801,171 issued July 30, 1957.

Suitable color-forming compounds or couplers which can be used in practicing the present invention include couplers producing cyan images, magenta images and yellow images such as those disclosed in columns 15-18 of U.S. Patent 3,046,129 of Graham et al.

The above-mentioned color-forming compounds produce dyes upon development of the exposed emulsion with color developers such as aromatic primary amino color developing agents, e.g., p-phenylenediamine color developing agents. Examples of such developing agents are shown, for example, in column 18 of the abovementioned Graham et al. U.S. Patent 3,046,129.

The silver halide emulsions employed in the present invention are of the developing-out type and can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The emulsions can be coarse or fine grain and may be prepared by any of the Well known procedures, e.g., single jet emulsions, double jet emulsions, Lippmann emulsions, ammoniacal eitnulsions, thiocyanate or thioether ripened emulsions, e c.

The emulsions can also be sensitized with chemical sensitizers, such as with reducing agents; sulfur; selenium or tellurium compounds; gold, platinum or palladium compounds; or combinations of these. Suitable procedures are described in Sheppard et al. U.S. Pat. 1,623,499; Waller et al. U.S. Pat. 2,399,083; McVeigh U.S. Pat. 3,297,447; and Dunn U.S. Pat. 3,297,446.

Likewise, the silver halide emulsions can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers each used along or in combination include thiazolium salts described in Brooker et al. U.S. Pat. 2,131,038 and Allen et al. U.S. Pat. 2,694,716; the azaindenes described in Piper U.S. Pat. 2,886,437 and Heimbach et al. U.S. Pat. 2,444,605; the mercury salts as described in Allen et al. U.S. Pat. 2,728,663; the urazoles described in Anderson et al. U.S. Pat. 3,287,135; the sulfocatechols described in Kennard et al. U.S. Pat. 3,236,652; the oximes described in Carroll et al. British Patent 623,448; nitron; nitroindazoles; the mercaptotetrazoles described in Kendall et al. U.S. Pat. 2,403,927; Kennard et al. U.S. Pat. 3,266,897 and Luckey et al. U.S. Patent 3,397,987; the polyvalent metal salts described in Jones U.S. Pat. 2,839,405; the thiuronium salts described in Herz et al. U.S. Pat. 3,220,839; the palladium, platinum and gold salts described in Trivelli et al. U.S. Pat. 2,566,263 and Yutzy et al. U.S. Pat. 2,597,915.

Spectral sensitizing dyes can be used to confer additional sensitivity to the light-sensitive silver halide emulsion of the multilayer photographic elements of the invention. For instance, additional spectral sensitization can be obtained by treating the emulsion with a solution of a sensitizing dye in an organic solvent or the dye may be added in the form of a dispersion as described in Owens et al. British Pat. 1,154,781. For optimum results, the dye may either be added to the emulsion as a final step or at some earlier stage.

sensitizing dyes useful in sensitizing such emulsions are described, for example, in Brooker et al. U.S. Pat. 2,526,632, issued Oct. 24, 1950; Sprague U.S. Pat. 2,503,776, issued Apr. 11, 1950; Brooker et al. U.S. Pat. 2,493,748; and Taber et al. U.S. Pat. 3,384,486. Spectral sensitizers which can be used include the cyanines, merocyanines, complex (tri or tetranuclear) merocyanines, complex (tri or tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines (e.g. enamine hemicyanines),

oxonols and hemioxonols. Dyes of the cyanine classes may contain such basic nuclei as the thiazolines, oxazolines, pyrrolines, pyridines, oxazoles, thiazoles, selenazoles and imidazoles. Such nuclei may contain alkyl, alkylene, hydroxyalkyl, sulfoalkyl, carboxyalkyl, aminoalkyl and enamine groups and may be fused to carbocyclic or heterocyclic ring sysetms either unsubstituted or substituted with halogen, phenyl, alkyl, haloalkyl, cyano, or alkoxy groups. The dyes may be symmetrical or unsymmetrical and may contain alkyl, phenyl, enamine or heterocyclic substituents on the methine or polymethine chain. The merocyanine dyes may contain the basic nuclei mentioned above as well as acid nuclei such as thiohydantoins, rhodanines, oxazolidenediones, thiazolidenediones, barbituric acids, thiazolineones, and malononitrile. These acid nuclei may be substituted with alkyl, alkylene, phenyl, carboxyalkyl, sulfoalkyl, hydroxyalkyl, alkoxyalkyl, alkylamino groups, or heterocyclic nuclei. Combinations of these dyes may be used, if desired. In addition, supersensitizing addenda which do not absorb visible light may be included, for instance, ascorbic acid derivatives, azaindenes, cadmium salts, and organic sulfonic acids as described in McFall et al. U.S. Pat. 2,933,390 and Jones et al. U.S. Pat. 2,937,089.

The various layers, including the photographic layers, employed in the practice of this invention can contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. 3,253,921; Gaspar U.S. Pat. 2,274,782; Silberstein et al. U.S. Pat. 2,527,583 and Van- Campen U.S. Pat. 2,956,879. If desired, the dyes can be mordanted, for example, as described in Jones et al. U.S. Pat. 3,282,699.

The sensitizing dyes and other addenda used 1n the practice of this invention may be added from water solutions or suitable organic solvent solutions may be used. The compounds can be added using various procedures including those described in Collins et al. US. Pat. 2,912,343; McCrossen et al. U.S. Pat. 3,342,604; Audran U.S. Pat. 2,996,287 and Johnson et al. U.S. Pat. 3,425,835.

The layers of the photographic element employed and described herein can be coated on a wide variety of supports. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support, which can be partially acetylated or coated with baryta and/or an alphaolefin polymer, particularly a polymer of an alpha-olefin containing 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylenebutene copolymers and the like.

The following examples will serve to illustrate the increased speed effect produced by the present disulfone compounds of this invention in photographic silver halide emulsions which contain a coupler.

EXAMPLES 1-3 A high speed gelatino silver bromoiodide emulsion which is digested to optimum sensitivity with a mixture of a labile sulfur compound of the type shown in U.S. Pat. 1,623,499 to Sheppard, and a gold compound of the type shown, for example, in U.S. Pat. 2,399,083, and which has been sensitized to the red region of the spectrum with a spectral sensitizing dye is coated onto a cellulose acetate film support over a layer of gelatin which had been coated onto the film support at a coverage of 454 milligrams of gelatin per square foot to provide a control emulsion coating. The silver bromoiodide emulsion contains the cyanforming coupler 5 [0c (2,4 di-n-amylphenoxy)butyramido]-2-heptafluorobutyramidophenol. In addition, the emulsion contains the cyan-forming coupler 1-hydroxy-2- [oc-(2',4'di-t6lt. amylphenoxy)-n-butyl]naphthamide. The couplers are added to the emulsion in the form of a finelydivided dispersion according to the procedure described in Example 2 of U.S. 2,801,171 to Fierke. A second portion of the foregoing emulsion is coated over a cellulose acetate support having thereon a layer of gelatin (454 mg./ft. containing bis(methylsulfonyl )methane at a coverage of 50 milligrams per square foot. A third portion of the emulsion is admixed with 50 milligrams per square foot of his (methylsulfonyl)methane and coated on a cellulose acetate film support coated with gelatin at a coverage of 454 mg./ft. The three elements are exposed on an Eastman Ib sensitometer for approximately second. The exposed elements are developed for 60 seconds at about 68 F. in a developer having the composition set forth below:

Sodium hexametaphosphate2.0 g. N-methyl-p-aminophenol sulfate-6.0 g.

Sodium sulfite, anhydrous50.0 g.

Hydroquinone-6.0 g.

Sodium carbonate monohydrate35 .0 g.

Potassium bromide2.0 g.

Sodium hydroxide20.0 g.

0.5% solution of 6-nitrobenzimidazole nitrate12.0 cc. 0.1% solution of potassium iodide10.0 cc.

Water to make 1 liter.

The elements are then washed thoroughly with water and are treated in a hardening bath having the following composition:

Potassium chrome alum crystals30.0 g. Water to make 1 liter.

Each element is then thoroughly washed with water and treated for 30 seconds in a solution having the following composition:

Sodium borohydride0.25 g. Sodium hydroxide-4.0 g. Water to make 1 liter.

The elements are then treated in a color developer having the following composition:

Benzyl alcohol-6.0 cc.

Sodium hexametaphosphate2.0 g. Sodium sulfite, anhydrous .0 g. Trisodium phosphate40.0 g. Potassium bromide-0.25 g.

0.1% solution of potassium iodide-10.0 cc. Sodium hydroxide-6.5 g.

Sodium hydroxide l 1.33 g. Ethylenediamine sulfate7.8 g. Citrazinic acid-1.5 g.

Water to make 1 liter.

1 4 amino N ethyl-N-(B methanesulfonamidoethyl)-mtoluldine sesquisulfate monohydrate.

The elements are then thoroughly washed with water and treated in a clearing and fixing bath having the following composition:

Sodium thiosulfatel50.0 g. Sodium bisulfite-20.0 g. Water to make 1 liter.

The elements are then treated in a bleach bath having the following composition:

Potassium dichromate5 .0 g. Potassium ferricyanide70.0 g. Potassium bromide-20.0 g. Water to make 1 liter.

The elements are again washed and treated once again with the clearing and fixing bath identified above. The elements are again washed and treated in a stabilizing bath having the following composition:

TABLE I Relative speed B1s(methylsulfonyhmethane (red) Example No.:

1 None present (control) 2 In the emulsion layer 126 3 In a contiguous gelatin layer 126 The foregoing examples illustrate that the disulfones of the present invention can be added to photographic silver halide emulsions or contiguous layers thereto to significantly increase the effective speed.

The photographic and other hardenable layers used in the practice of this invention can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes, ketones, carboxylic and carbonic acid derivatives, sulfonate esters, sulfonyl halides, and vinyl sulfonyl ethers, active halogen compounds, epoxy compounds, aziridines, active ole-fins, isocyanates, carbodiimides, mixed function hardeners and polymeric hardeners such as oxidized polysaccharides like dialdehyde starch and oxyguargum and the like.

The photographic emulsions and elements described in the practice of this invention may contain various colloids alone or in combination as vehicles, binding agents and various layers. Suitable hydrophilic materials include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides, such as dextran, gum arabic and the like, and synthetic polymeric substances such as water-soluble polyvinyl compounds like poly(vinylpyrrolidone), acrylamide polymers and the like.

The photographic elements used with this invention may contain antistatic or conducting layers, such layers may comprise soluble salts, e.g., chlorides, nitrates, etc., evaporated metal layers, ionic polymers such as those described in Trevoy U.S. Pat. 3,428,451.

The various photographic layers may contain plasticizers and lubricants such as polyalcohols, e.g., glycerin and diols of the type described in Milton et al. U.S. Pat. 2,960,404; fatty acids or esters such as those described in Robijns U.S. Pat. 2,588,765 and Duane U.S. Pat. 3,121,- 060; and silicone resins such as those described in Du Pont British Pat. 955,061.

Likewise, the various photographic layers employed in the practice of this invention may contain surfactants such as saponin; anionic compounds such as the alkyl aryl sulfonates described in Baldsiefen U.S. Pat. 2,600,831; amphoteric compounds such as those described in Ben- Ezra U.S. Pat. 3,133,816; and water soluble adducts of glycidol and an alkyl phenol such as those described in Olin Mathieson British Pat. 1,022,878. Also, the photographic elements may contain matting agents such as starch, titanium dioxide, zinc oxide, silica, polymeric beads including beads of the type described in Jelley et al., U.S. Pat. 2,992,101 and Lynn U.S. Pat. 2,701,245.

The photosensitive elements of the invention can contain brightening agents including stilbenes, triazines, ox-

azoles and coumarin brightening agents. Water soluble brightening agents may be used such as those described in Albers et al. German Pat. 972,067 and McFall et al. U.S. Pat. 2,933,390 or dispersions of brighteners may be used such as those described in Jansen Germany Pat.

1,150,274, Oetiker et al. US. Pat. 3,406,070 and Heidke French Pat. 1,530,244.

Various coating procedures including dip coating, air knife coating, curtain coating, or extrusion coating using hoppers of the type described in Beguin US. Pat. 2,681,- 294 may be employed in coating the present photographic layers. If desired, two or more layers may be coated simultaneously by the procedures described in Russell US. Pat. 2,761,791 and Wynn British Pat. 837,095. This invention also can be used for silver halide layers coated by vacuum evaporation as described in British Pat. 968,- 453 and Lu Valle et al. US. Pat. 3,219,451.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications may be elfected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A process for increasing the speed of a photographic silver halide emulsion which comprises developing an exposed silver halide emulsion with an aromatic primary amino color developing agent in the presence of a coupler capable of coupling with the oxidation products of said color developing agent to form a dye and a 1,1 bis sulfonyl-alkane speed increasing agent.

2. The process of claim 1 wherein said speed increasing agent is provided in said silver halide emulsion.

3. The process of claim 1 wherein the said speed increasing agent is provided in a layer contiguous to said silver halide emulsion.

4. The process of claim 1 wherein said 1,1 bis sulfonyl alkane has the formula a Rr-S O2C 1HSO2-Rz wherein R and R each represent an alkyl group containing 1 to 4 carbon atoms and R represents H or an alkyl group containing 1 to 4 carbon atoms.

5. The process of claim 4 wherein R and R each represent methyl, ethyl, hydroxyethyl, carboxymethyl, or carboxyethyl groups and R represents H.

6. The process of claim 5 wherein R and R each represent a methyl group.

7. A photographic silver halide emulsion having a color-forming coupler compound contiguous thereto which is capable of coupling with the oxidation products of an aromatic primary amino color developing agent to produce a colored compound, said emulsion containing a sensitizing amount of a 1,1 bis sulfonyl alkane.

8. The silver halide emulsion of claim 7 wherein said emulsion is additionally sensitized with a labile sulfur compound and a gold salt.

9. The silver halide emulsion of claim 7 wherein said 1,1 bis sulfonyl alkane has the formula s Ri-S O,C|1HS O R wherein R and R each represent an alkyl group containing l to 4 carbon atoms and R represents H or an alkyl group containing 1 to 4 carbon atoms.

10. The silver halide emulsion of claim 9 wherein R and R each represent methyl, ethyl, hydroxyethyl, carboxymethyl, or carboxyethyl groups and R represents H.

11. The silver halide emulsion of claim 10 wherein R and R each represent a methyl group.

12. A photosensitive element comprising a support having thereon a photographic silver halide emulsion layer having a color-forming coupler compound contiguous thereto which is capable of coupling with the oxidation products of anaromatic primary amino color developing agent to produce a colored compound, said photosensitive element containing a sensitizing amount of a 1,1 bis sulfonyl alkane speed increasing agent.

13. The photosensitive element of claim 12 wherein said speed increasing agent is provided in said silver halide emulsion layers.

14. The photosensitive element of claim 12 wherein said speed increasing agent is provided in a layer contiguous to said silver halide emulsion layer.

15. The photosensitive element of claim 12 wherein said 1,1 bis sulfonyl alkane has the formula a R1-SOg( )HSOg-Rg wherein R and R each represent an alkyl group containing l to 4 carbon atoms and R represents H or an alkyl group containing 1 to 4 carbon atoms.

16. The photosensitive element of claim .15 wherein R and R each represent methyl, ethyl, hydroxyethyl, carboxymethyl, or carboxyethyl groups and R represents H.

17. The photosensitive element of claim 15 wherein R and R each represent a methyl group.

References Cited UNITED STATES PATENTS 10/1962 Burness et al. 96100 7/1969 Burness et al 9610-7 US. Cl. X.R. 96100 

